Conventionally, a substrate connecting structure for connecting electrically and mechanically two substrates facing each other has a construction shown in FIG. 5. FIG. 5 shows, for example, a substrate connection structure 3 for connecting a main substrate 1 (as a first substrate) of a vehicular information device and a ICM substrate 2 (i.e., IVI complete module or in-vehicle information complete module) (as a second substrate) as a different substrate. The substrate connection structure 3 includes a connector 4 (or a compression connector) and a screw 5 with a head for screwing.
The connector 4, for example, has a main body 4a made of resin in which a nut 4b is embedded. Further, the main body 4a of the connector 4 includes multiple connection terminals 6. Each connection terminal 6 has a lower end 6a protruding from a bottom surface of the main body 4a, and an upper end 6b protruding from a top surface of the main body 4a. 
The connection terminal 6 of the connector 4 is soldered on a pattern of the main substrate 1 by a flow-soldering manner. In this case, a fine gap is preliminarily formed between the connector 4 and the main substrate 1 in order to secure coplanarity (which is uniformity of an undermost surface of a terminal or an electrode in an element with respect to an attachment surface).
On the other hand, a first screw insertion hole 2a is formed in the ICM substrate 2. The screw 5 is inserted into the first screw insertion hole 2a, and the screw 5 is fastened with the nut 4b. In this case, the screw 5 is screwed until the upper end 6b of the connection terminal 6 sufficiently press-contacts the pattern of the ICM substrate 2. Here, a technique described in the Patent Literature No. 1 is similar to a technique of the substrate connection structure 3 having the above construction.
In the structure shown in FIG. 5, since a force at the time of fastening with the screw 5 is directly applied to a soldered portion of the connection terminal 6, large load is applied to the soldered portion. Accordingly, a contact failure may occur or a crack may arise at the soldered portion under usage environment (such as vibration and outside temperature change) of the vehicular information device. Further, the fastening force of the screw 5 functions a force for removing the lower end 6a of the connection terminal 6 from the main substrate 1, and therefore, the soldered portion may be separated.